...

It is basically functional, but unambiguously ugly.

We also have these slides which sketch a UI. They are similarly ugly.

All of the above, despite its ugliness, should be reviewed to understand the types of functionality that have been envisaged so far.

Functional Specification

There are essentially the following main parts: microfrontend configuration, extension configuration, and the UI editor.

...

Any extension can technically be added to any slot, but few extension-slot pairings will actually work correctly. It's unclear how we should address this, but perhaps the simplest way would be to assign slots and extensions "types" so that they can be associated with each other. Each "type" would have some expected shape of state object. Alternatively, extensions could make their requirements known to the extension system (the extension system already has access to the state provided by slots).

Image Added

Here we see the "remove" element editor, which offers a multi-select of the extensions which are currently attached to the slot (and thus available to be removed).

UI Editor

The UI Editor provides the administrator with a visual understanding of what the configuration means.

For the microfrontend configuration, it's simply "edit buttons" in sensible places in the UI which allow the admin to "hop" to the relevant piece of config. For example, turning on the UI Editor, they might see a little Edit button by the logo on the login page. When they click that button, they would be taken to the relevant section of the configuration in the Implementer Tools panel.

The bulk of what the UI Editor does, however, has to do with extensions. It makes it clear to the administrator where all the slots and extensions are.

It should probably also provide features for visually editing the extension configuration—buttons that trigger the corresponding config changes to e.g. remove an extension or reorder it within a slot. This is featured prominently in the presentation linked above.

Challenges

The shape of the configuration is subject to change. New microfrontends may do new and previously unanticipated things with config structure.

The same is true of extensions and extension slots. Who knows what insane things people might try to use them for.